1. Field of the Invention
The present invention relates to a radiation detecting cassette having therein a radiation conversion panel for detecting a radiation that has passed through a subject and converting the detected radiation into radiation image data, and a radiation image capturing system incorporating such a radiation detecting cassette, and more particularly the present invention relates to a radiation detecting cassette for transmitting radiation image data to an external device by way of wireless communications, and a radiation image capturing system incorporating such a radiation detecting cassette.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which captures a radiation image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiation image in a phosphor and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor. In such a radiation conversion panel, the radiation film with the recorded radiation image is supplied to a developing device to develop the radiation film, or the stimulable phosphor panel is supplied to a reading device to read the radiation image, to obtain the radiation image as a visible image.
In the medical examination room or the like, it is necessary to read out and display a recorded radiation image immediately from a radiation conversion panel after the radiation image is captured for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting a radiation directly into an electric signal or converting a radiation into visible light with a scintillator and then converting the visible light into an electric signal to read out a detected radiation image. The radiation conversion panel is separate from a console as a controller and a radiation source because the radiation conversion panel is used to capture radiation images of various areas of patients (see Japanese Patent No. 3494683, Japanese Laid-Open Patent Publication No. 2005-007086, and Japanese Laid-Open Patent Publication No. 2005-208269).
According to the technology disclosed in Japanese Patent No. 3494683, a radiation detecting cassette (hereinafter also referred to as “cassette”) having therein a radiation conversion panel transmits a radiation image signal as a wireless signal to an external signal processor (Paragraph [0043], FIG. 5 of Japanese Patent No. 3494683). According to the technology disclosed in Japanese Laid-Open Patent Publication No. 2005-007086, the remaining power level of a battery is detected, and the number of radiation images that can be captured is calculated (Paragraph [0033] of Japanese Laid-Open Patent Publication No. 2005-007086). According to the technology disclosed in Japanese Laid-Open Patent Publication No. 2005-208269, the remaining power level of a battery is detected, and the application of X-rays is canceled if the detected remaining power level is smaller than a predetermined value (Paragraphs [0017]-[0022] of Japanese Laid-Open Patent Publication No. 2005-208269).
According to Japanese Patent No. 3494683, a radiation detector (a solid-state detector, a scanning pulse generator, and a transfer register) and a transmission processing circuit are energized by a single power supply (Paragraphs [0033] and [0041] of Japanese Patent No. 3494683). Since the electric power from the power supply is used both for radiation detection and for wireless data transmission, the electric power from the power supply is consumed faster than if it is used only for radiation detection. As a result, the amount of electric power from the power supply which is necessary to capture a required number of radiation images may possibly run short quickly.
According to Japanese Laid-Open Patent Publication No. 2005-007086 and Japanese Laid-Open Patent Publication No. 2005-208269, though the remaining power level of the battery is detected and X-ray images are captured depending on the detected remaining power level of the battery, nothing is shown about the acquisition of radiation image data through the effective use of a low remaining battery power level.